In order to rout various sizes of square and rectangular grooves and recesses, various designs for adjustable rectangular guides have been proposed. Examples of these designs are found in the literature including Spielman, P., The New Router Handbook (New York: Sterling Publishing Co., 1993) at pp. 211-212; and Spielman, P., Router Jigs and Techniques (New York: Sterling Publishing Co., 1988) at pp. 220-223. While these prior art designs teach an adjustable four-sided frame for guiding a router, they suffer from a number of limitations including the requirement of having to adjust each corner of the frame in order to set the desired length and width. In addition, these prior art framing guides are designed so that the router base rides on top of the frame guide members rather than the router base being contained within the frame guide members, thus requiring the router operator to hold the router partly on and partly off a supporting base. Furthermore, the rectangular frame guides found in the prior art do not allow any flexibility in routing grooves or recesses which are somewhat off-square, i.e. a parallelogram, or which do not have any parallel sides, i.e. a trapezoid. In addition, it is not possible or practical to use the prior art frame guides on surfaces which are vertical or angled.